1. FIELD OF THE INVENTION
The present invention relates to method and apparatus for diagnoses by detection of disorders in genomic substances of organisms, which use a molecular biological technique.
2. RELATED ART STATEMENT
A method for detecting disorders in genomic substances by the use of a nuclease is discussed in Nature 313 (1985) pp 495-498. In this method, whether a hybrid between a target DNA fragment and a DNA probe is complete or incomplete is investigated. This method is characterized in that S1 nuclease is used for detecting an incomplete portion. S1 nuclease digests only single-stranded DNA but not double-stranded DNA. Therefore, when hybridization between a target genomic substance fragment and a DNA probe is complete and they form a double strand, the resulting hybrid is not digested. On the other hand, when the hybridization is not complete and a single-stranded portion exists, the resulting hybrid is digested and shortened. Accordingly, disorders in a target DNA fragment can be detected by forming a hybrid between the target DNA fragment and a DNA probe labeled with a radioisotope or the like, treating the hybrid with S1 nuclease, measuring the molecular weight of the hybrid by electrophoresis, and judging whether the hybrid is complete or incomplete.
In addition, this method is applied to hybrids formed between target DNA or RNA fragments and RNA probes, by the use of a nuclease RNase A, as discussed in Science 230 (1985) pp 1242-1246 and Proc. Natl. Acad Sci. U.S.A. 82 (1985) pp 7575-7579.